Radio signals skew birds’ internal navigation

Migrating birds might lose their way when exposed to the electromagnetic noise from radio
signals and electronic devices, researchers have found.

Birds that fly north or south with the seasons rely on Earth’s magnetic field to sense where
they’re going. Even birds placed in windowless rooms will try to fly in their preferred migratory
direction.

But when researchers placed European robins in wooden huts on the University of Oldenburg campus
in densely populated northwestern Germany, the birds were unable to orient themselves.

Suspecting that electromagnetic signals were confounding the robins’ magnetic compasses, the
researchers moved them to electrically grounded, aluminum-screened huts that blocked noise between
50 kHz and 5 MHz. The birds regained their sense of direction.

The researchers repeated the experiments during migrating seasons for seven years, before
publishing in the journal
Nature.

— The New York Times

New neurons found to overwrite old memories

The inability of adults to recall experiences from early childhood might be linked to the
creation of neurons in the brain.

Throughout a person’s life, neurons are constantly made in the hippocampus, a region of the
brain associated with memory. To see whether this process, known as neurogenesis, could drive the
loss of childhood memories, researchers ran tests with animals trained to fear a particular
environment through electric shock.

Adult mice that were made to run on a wheel, an activity that encourages the birth of neurons,
quickly lost their fear of the troubling environment, while mice that didn’t run seemed to retain
their memories. Infant mice treated with drugs to slow neurogenesis also were better at retaining
memories of the shocks than those not given drugs.